Energy and fuels are essential in modern life. Most widely used type of fuels are fossil fuels. Fossil fuels, including petroleum oil, are essentially hydrocarbons containing carbon and hydrogen in various ratios.
Petroleum oil, like any carbon-containing fuel, forms carbon dioxide upon its combustion, and therefore is not renewable on the human timescale. Also, because carbon dioxide is a greenhouse gas, combustion of oil contributes to global warming. It has been suggested to mitigate harmful carbon dioxide emissions by imposing carbon quota or by capturing carbon dioxide emissions and sequestering it underground or at the bottom of the sea. Sequestration, however, is a costly and only a temporary solution that presents a risk that sequestered carbon dioxide may be released with deadly catastrophic consequences in geological events such as earthquakes and slides.
Thus, it would be desirable to make petroleum oil use environment-friendly by effectively addressing its carbon dioxide emission and at the same time render it a regenerative carbon source.